Electric circuit breaker



Filed July E. LANGE ELEULRlC CIRCUIT BREAKER 2 Sheets-Sheet l Inventor E. LANGE 4 ELECTRIC CIRCUIT BREAKER Oct. 13, 1959 2 Sheets-Sheet 2 Filed July 16, 1958 Inventor (Q a United States Patent ELECTRIC CIRCUIT BREAKER Emil Lange, Ville dAvray, France Application July 16, 1958, Serial No. 749,034

6 Claims. (Cl. 200-150) This invention relates to an electric switch of the kind in which the arc is quenched by fluid quenching medium flowing under pressure produced by the arc itself.

In such switches the rapid production of the pressure and full use of the fluid medium are of the greatest importance for reliable operation in quenching the are.

In order to quench the are within the period of one current alternation a powerful pressure wave or a very rapid pressure rise is necessary, and it is also necessary to utilise the available quenching medium as fully as possible for the quenching operation, since due to the necessarily small volume of the quenching chamber only a small amount of quenching medium is available.

In the constructions known hitherto, due to the contact movement much time is required for the production of pressure, so that usually time enough for several current alternations elapses before the requisite pressure rise has been produced in the quenching chamber. Due to the introduction and withdrawal of the movable contact through an aperture in the quenching chamber sealing is not possible, so that some of the quenching medium can escape from the chamber without having served for the quenching of the arc.

It is therefore an object of the invention to provide an improved electric switch of the kind referred to.

According to the invention there is provided an electric switch in which the arc is quenched by fluid quenching medium flowing under pressure produced by the arc itself, characterised in that it comprises a rotatable drive part such as a roll or disc, which carries a current bar for the normal current passage and also bridge contacts which during rotation of the drive part serve firstly for the bridging over of fixed open interruption gaps and then draw out the arcs at these interruption gaps for the pressure production. In the switching-01f movement firstly the current passage through the current bar is interrupted without arcing, so that the current now only flows through the bridge contacts and through the contacts serving for drawing the arms. On opening of the I bridge contacts arcs are drawn into the middles of the gaps between the contacts of the open interruption gaps in the quenching chamber, and the arcs then burn between the contacts of the open interruption gaps.

The bridge contacts are preferably electrically con nected by intermediate contacts with the fixed contacts, the spacing of these intermediate contacts being greater than that of the fixed contacts. Those intermediate contacts resting on the bridge contacts are preferably disposed towards the contact tips and serve for the arc travel towards the middles between the fixed contacts. The bridge contacts preferably arranged on a roll as surface contacts, with triangular shapes and at first bridge-over the open interruption gaps, in order then to guide the arcs towards the middles of the open interruption gaps, so that the arcs then burn between the contacts of the open interruption gaps. For the purpose ice of feeding the arcs to the contacts of the open interruption gaps the quenching chamber is preferably provided with appropriate slots, through which the arcs are guided by means of the intermediate contacts on to the tips of the contacts of the open interruption gaps. Through the bridge contacts it is possible to draw first one or more pressure-producing arcs and then the arcs to be quenched. For the reduction or alternation of the current to be interrupted it is possible to connect current-limiting devices such as resistances or chokes between the contacts of the arcs to be quenched. The outflow openings can be closed off by a valve which controls the flow and pressure of the quenching medium.

In the accompanying drawings the invention is illustrated by way of example,

Fig. 1 being a sectional elevation of a switch according to the invention and Fig. 2 a cross-section of the switch.

The illustrated switch comprises a quenching chamber 1 with outflow openings 2 and 3 together with a housing 4. The quenching chamber 1 has end caps 5 and 6 on which terminals 7 and 8 are arranged.

In the quenching chamber 1 there are provided two fixed open interruption gaps for the quenching of the arcs, which gaps are formed between contacts 9, 10 and 11, 12. The contacts 10, 11 are situated near to nozzles 13, 14 of insulating material. These nozzles 13, 14 are the direct outflow openings of the quenching chamber 1.

The contacts 10, 11 are extended towards the interior of the quenching chamber 1, and form with the opposite contact tips 15, 16 a third fixed and open interruption gap in the quenching chamber 1, this third gap serving for the pressure production. In order to make this pressure production fully effective, between the contacts 15, 16 there is an insert 17 with a passage which has a small diameter in the middle and widens conically towards the contacts 15, 16. Due to this arrangement the root points of the arcs burning on the contacts 15, 16 are effectively exposed to a flow of quenching medium.

Due to the length of the contacts 10, 15 and 11, 16, spaces 18, 19 are provided in the quenching chamber 1, in which spaces 18 and 19 the arc cannot burn. The quenching medium in these spaces 18, 19 is not heated by the arc.

The contact tips 10, 11, 15, 16 and the contacts 9 and 12 are connected with intermediate contacts 20, 21, 22, 23, 24 and 25. These intermediate contacts serve on the one hand as pressure contacts and on the other hand as guides for rapid travel of the arcs to the contact tips 10, 11, 15 and 16. For this reason these intermediate contacts are set back in relation to the contact tips so that the spacing of the intermediate contacts is greater than that of the contact tips. The arcs are compelled by this arrangement to burn on the contact tips 10, 11, 15 and 16, since here are the smallest gaps.

Between the intermediate contacts 25, 20-21, 22- 23, 24 the quenching chamber 1 and the nozzles 13, 14 and the insert 17 are pierced by slots 26, 27 and 28, which permit the guidance of the arcs to the contact tips.

In the housing 4 there is a rotary drive part in the form of a roll or drum 29, of insulating material, which roll or drum is firmly connected with a drive shaft 30. In the roll or drum 29 there is arranged a current bar 31, for the normal current transmission, the bar 31 being engaged by pressure contacts 32, 33, which are connected to the terminal caps 5 and 6.

On the roll or drum 29 there are also secured bridge contacts 34, 35, and 36 in the form of contact plates of triangular shape which rest with their wide parts engaging the intermediate contacts 25, 2021, 22 and 23, 24, when the switch is closed. When the switch is open the points of the bridge contacts 34;, 35, and 36 are situated in the middles of the interruption gaps between the contacts 9, 15, 16 and 11, 12.

T e que h m er 1 to ethe h h ou i g 4 is held by a mounting 37, and can be secured on an appropriate insulator.

The arrangement described above operates as follows:

When the switch is in the closed position as shown, the current flows directly through the terminal 7-the pressure contact 32-the current bar 31 -the pressure contact 33 and the second terminal 8.

At the same time, the current flows indirectly also through the connection contact 9 t h e bridge contact 34-theintermediate contacts 20, 2. 1 .the bridge contact 35.the intermediate contacts 22, 23the bridge contact 36--the intermediate contact 24 and the terminal 3.

During opening of the switch the roll or drum 2 9 is rotated by means of the shaft 30, and the contacts 32,, 33, without forming an arc, leave the current bar .31, so that now the current flows only through the quenching chamy y of the d contac s 34, 35 and 36- During further rotation of the roll 29, the wide parts of the bridge contacts 34, 3,5 at first still slide on the intermediate contacts 25 20, 2 1, 22, 23 and 24.

Due to the triangular shape of the bridge contacts, the intermediate contacts are left by the bridge contacts and six arcs are formed between the contacts, 25, 3434, 2021, 35--35, 22-23, 36 and 3 62 4,

Due to the shape of the bridge contacts and of the 9 intermediate contacts, these six arcs are rapidly drawn out in length and conducted towards the middles of the open interruption gaps, so that these six arcs join up and burn as three arcs between the contacts 9, 10-45, 16-11, 12.

Due to the very rapid extension of the three arcs, to the overall length of the interior of the quenching chamber, a rapid and great pressure rise is produced and the roots of the arcs at the contacts 10, 11 and 15, 16 are immediately exposed to a very effective flow of quenching medium, and the quenching of the arcs takes place readily and reliably.

The spaces 18,19 are of particular importance for the quenching operation, since. there the entire available amount of quenching medium is not pro-warmed by the arcs and the cold quenching medium flows over the contacts 1th, 11 and very efiectively influences the arc quenchmg.

By appropriate enlargement or lengthening of the spaces 18, 19 it is easy to increase still more this very effective influencing of the quenching operation.

It is possible to introduce, into these spaces 18, 19 conductive tubes, upon which the contact tips 10, and 11, 16, are mounted. Such tubes, which serve on the one hand to aid the current transmission, can assist on the other hand in the cooling of the quenching medium which issues from the insert 17.

These tubes can also be produced from a resistant material, thus limiting the current which is passing and which has to be interrupted.

In the device as described the quenching medium available in the quenching chamber is substantially fully utilised, since it can only escape through the outflow openings, which serve for the quenching of the arcs.

In the example of embodiment the retatable drive part is constructed as a roll 29; naturally it is also possible to use other shapes, such as a disc or drum.

As a fluid quenching medium it is possible to use air, gas, or a liquid, or inert powder.

I claim:

1. An electric switch of the kind in which at least one are is quenched by quenching medium flowing under pressure produced by the arc itself, comprising in combination a housing, a quenching chamber mounted on said housing and having outlets at two ends, a terminal at each end of said quenching chamber, a plurality of fixed contacts arranged in said quenching chamber to form a plurality of fixed open interruption gaps, intermediate contacts secured to said fixed contacts and extending towards the middle of said housing, an insulating rotatable drive part in said housing, a current bar extending through said rotatable drive part, pressure contacts connected one to each of said terminals and engaging said current bar in the closed condition of the switch, and bridge contacts on said rotatable drive part and engaging said intermediate contacts so that in the closed condition of the switch each of said fixed open interruption gaps is bridged by one of said bridge contacts, the arrangement being such that when said rotatable drive part is rotated to open the switch said bridge contacts bridge said open interruption gaps whilst said current bar is moved clear of said pressure contacts and then draw out arcs in said open interruption gaps.

2. A switch as claimed in claim 1, said bridge contacts being shaped to draw said arcs during opening of the switch to the middles of said open interruption gaps. and leave said arcs burning one in each of said open interruption gaps directly between two of said fixed contacts.

3. A switch as claimed in claim 1, eachone of said fixed open interruption gaps being shorter than the space between two of said intermediate contacts disposed one at each end of that one of said gaps.

4. A switch as claimed in claim 1, win oi said intermediate contacts having edges running obliquely towards the tips of some of said fixed contacts, so that the ends of said arcs travel along said edges to said tips.

5. A switch as claimed in claim 1, each of said bridge contacts being of substantially triangular shape and disposed to draw a pair of arcs to the middle ofonc of said fixed open interruption gaps and cause said pair of arcs to join into a single are burning in said one of said fixed open interruption gaps during opening of the switch.

6. A switch as claimed in claim 1, said housing and said quenching chamber being provided with communication slots and said intermediate contacts extending through said slots, the arcs which during opening of the switch initially extend between said intermediate contacts and said bridge contacts being guided in said slots.

References Cited in the file of this patent UNITED STATES PATENTS 2,100,753 Schoiield et al Nov. 30, 193.7

2,416,185 Leeds Feb. 18, 1947 2,507,971 Guillaume et al. May 16, 1950 FOREIGN PATENTS 477,853 Germany Iunel8, 1929 583,539 Germany c Sept. 5, 1933 

